Method of heat-treating flanges and the like



A ril 29, 1947. O 2,419,619

METHOD OF HEAT TREATING FLANGES AND THE LIKE F'iIed Feb. 15, 1943 2 Sheets-Sheet 1 r Ir. r'v "1 27 25 :IJ' I A34. l I "r a I i? Q; "/2 i i I Z8 26 g /6 M Li -v5 1 L IL L..! J

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Maw/MA A. O. WOOD April 29, 1947.

METHOD OF HEAT TREATING FLANGES AND THE LIKE Filed Feb. 13. 1945 2 Sheets-Sheet 2 INVENTOR.

Patented Apr. 29, 1947 METHOD OF HEAT-TREATING FLANGES AND THE LIKE Alden 0. Wood, Pal-ma, Ohio, assignor to The Ohio Crankshaft Company, Cleveland, Ohio, a corporation of Ohio Application February 13, 1943, Serial No. 475,833

3 Claims. 1

The present invention relates as indicated to a method of heat treating flanges 01 articles such as shafts and is well adapted to heating projectlng parts other than flanges of such articles. Heretofore, it has been difficult to limit heating to surface zones of selected parts of a projection, such as a flange of a shaft, and to a surface zone of a part of the shaft adjacent thereto and to so control the distribution of heating in both the flange and the shaft as to effectively heat the fillet joining the two surface zones. The inductor hereinafter described is similar in some respects to the inductor shown and described in copending application Serial No. 349,411, by F. S. Denneen and W. C. Dunn, filed August 2, 1940.

Numerous machines in their construction require shafts and other such parts having flanges or other transversely projecting members serving as shoulders for supports or other purpose, which members must be hardened either on one face only or on both faces. Such flanges or shoulders may require to have hardened outer cylindrical or end surfaces or a face of a flange may be required to be hardened over a limited area only to resist wear. In addition, to provide rigidity it is frequently required that hardness extend into the part of the shaft adjacent to the flange or shoulder, particularly into the angle or flllet between the side of the flange and the shaft. Further, when hardness is required in a cylindrical part of the shaft, this hardness must frequently be carefully controlled as to its area, its depth contour and its relation to such hardened zone as may be provided in the flange adjacent thereto. Sometimes the flange or shoulder is formed as a separate piece which must be brazed or otherwise fused to the shaft, which fusing is readily accomplished during the heating step in the method hereinafter described.

The chief object of the present invention is to provide means and method for hardening selected areas of a flanged shaft. Another object is to provide means and method for controlling the hardness in such selected areas both as to depth and degree of hardness. A further object is to provide means adapted to harden two intersecting surface zones, the said zones making a substantial angle with each other and to simultaneously control the hardening in both the zones and in the region of intersection. Additional objects will become apparent from the following description and appended claims.

With the above and other objects in view, the said invention then consists of the apparatus herein described together with the method employed in the use of this or similar apparatus to accomplish the results herein set forth. One form of the apparatus is shown in the annexed drawing in which:

Fig. 1 is a sectional view showing the lower half of the preferred form of the apparatus taken as indicated at l--| of Fig. 2 and showing a flanged shaft partly in section and in position to be heated in the apparatus.

Fig. 2 is a vertical section at 2-2 of Fig. 1. a

Fig. 3 is a sectional elevation taken as indicated at 33 of Fig. 2.

Fig. 4 is an elevation showing means for supporting the work piece.

Fig. 5 is a diagrammatic plan view of a modification of my apparatus.

Fig. 6 is an elevation of the modification shown by Fig. 5.

In general the invention comprises an inductor of compound form shaped to lie simultaneously in closely spaced relation with two surfaces of the article to be treated, elements of the surfaces lying in different planes and the planes being at substantial angles with each other, such as a cylindrical surface of a shaft and a side of a flange on the shaft. In the apparatus illustrated means is provided for rotating the article relatively to the inductor, but such rotating or other movement during heating is not always required, limited distribution of heating and quenching being satisfactorily accomplished without such movement.

In the form of apparatus illustrated by the drawing the shaft in having flange H is heat treated to provide hard surface zones substantially of the form shown by the closely spaced cross hatching at l2 and i3 joined by a hardened area in the fillet at I311. The inductor I4 is formed from copper tubing flattened to provide a wide and thin cross section with a passage for cooling fluid as shown at l5. Sections of this flattened tubing are joined, usually by brazing, to provide an inductor of the general form shown in Fig. 1, which is then bent substantally to the form shown in Fig. 3 to provide a curved surface at 15c adapted to lie substantially concentric with and close to shaft H]. In this form the inductor has a substantially continuous edge I6 lying in closely spaced relation with the side and outer peripheral surfaces of the flange II, a flat side which has been bent to the desired form, lying closely to the cylindrical portion of the shaft as shown at lid.

The apparatus is provided with a frame I! supporting two enclosure members for carrying the inductor l4 and for enclosing the flange H to be hardened. The enclosure members are usually made of heat resistant insulating material. An upper surface of the lower enclosure member I8 is shaped to conform with and supportingly engage a lower surface of the inductor. The upper enclosure member l9 serves as clamp bearing on an upper surface of inductor to hold the inductor firmly in place between the two members. Semicylindrical coniplementary recesses are provided in the adjacent sides of the two members forming a cylindrical chamber 20 to receive the flange l l with suitable clearance on both the sides of the flange and on its periphery. The upper member is is readily r movable to permit the insertion of the flange l 2, members [9a serving to guide this member into correct position.

Outer sides of both the upper and lower enclosure members are recessed as at 2! to provide quenching fluid delivery chambers, these chambers having presswood covers 2 la attached to the enclosure member A multiplicity of passages such as 22 are directed from these quenching fluid chambers into the cylindrical chamber, these passages being arranged at such angles as to effectively quench all heated parts of flange H and adjacent parts of shaft particularly the fillet at [3a. Quenching fluid is delivered to the delivery chamber 2i by valve controlled piping 23 and escapes from chamber 25 through the annular passages 24 around the shaft l6, effectively cooling the shaft surfaces.

Inlet and outlet passages for supplying cooling fluid to the inductor are shown at 25 and 25 respectively. A source of periodically varying current of proper frequency shown diagrammatically is connected by means of leads 2'! and 23.

For the purpose of distributing and equalizing heating resulting from current induced in shaft ID, the shaft is so supported as to be rotated during heating and/or during subsequent quenching. For this purpose one end of the shaft is secured in and supported by rotating chuck shown at 29. This chuck is driven by suitable means such as by an electric motor and turns at a preselected s eed. The opposite end of the shaft is supported on pair of idling rollers 30 and 31 permitting easy nd quick removal of the shaft when upper member l has been removed. These rollers are of correct diameter and spacing and are supported at the correct elevation to bring the center of this opposite end of the shaft into coaxial lignment with the chuck 29. Shafts such as 33 and 34 for supporting the rollers are carried on roller type bearings in the portion 35 of the frame of the apparatus.

It will be apparent that the apparatus can be made in various forms to provide almost any desired distribution of hardness or any desired form of hardened zone. The inductor is readily formed to increase the air gap between the cylindrical part of the flange and th inductor at M to reduce heating in this cylindrical part and thus to confine hardening to the sides of the flange. Likewise hardness in the cylindrical part of the shaft lying adjacent to the part ita of the inductor is readily reduced by increasing the air gap at this region,

Current flowing in an inductor disposed as shown in Fig. l induces current in the flange H and in adjacent parts of the shaft !3 which is opposite and substantially parallel with the cur rent in the inductor. This current thus flows around the flange substantially in a diametral plane, effectively heating only that part of the flange and shaft lying adjacent to the inductor, the heating being confined principally to the region indicated by the closely cross hatched parts shown in Fig. 1. It is thus necessary to rotate the shaft during heating to distribute the heat uniformly in the zones of the periphery and sides of t e flange and in the periphery of the shaft adjacent to the flange.

The curved part of the inductor at lfia is often omitted so that the inductor assumes the form of a U-shaped loop, as shown in Figs. 5 and 6.

fa tangent to a 5: is desired to provide with a hardened peripheral zone and its edge lies in closely spaced relation with the side of flange 52 which it is desired to provide with a hard thrust face 53, the edge of the branch being substantially parallel with a chord of the circle forming the face of the flange.

If it is desired not to harden the peripheral surface zone of the flange or the opposite face 55, the inductor is formed so that the branch 56 lies at substantial distances from these surfaces, thus dispersin the flux field through adjacent space and preventing an effective rise in temperature in thes regions. Hardening would then be accomplished in a peripheral zone of the shaft such as 5'! lying at some distance from the flange unless this branch or a part of it were moved away from the shaft far enough to prevent undesired heating in this zone. This moving of the branch of the inductor is accomplished by bending the branch. at some convenient place or by twisting the portion 58 as shown at 56a in Fig. 6. Cooling water is supplied to this inductor by piping at 53, and current of suitable frequency is delivered by supply lines 60.

In the appended claims lateral face of the flange refers to the surface extending transversely and usually at right angles to the axis of the shaft. Elements of this surface, however, may form angles other than right angles with the shaft axis. Further, the surface is not necessarily flat, but may be conical or have a fragmentary cylindrical or other form. By inner side face of the U-shaped inductor is meant one of the oppositely disposed faces forming the inner surface of the U-shaped loop, which loop is formed from the two substantially parallel side conductors and the either curved or straight transverse end conductor joining the side conductors at the closed end of the loop. It will be understood that flange and shoulder are general terms and are applied to a variety of projections on shaft, other than simple cylindrical discs.

Hardening a face of a flange and an adjacent part of a shaft is often accomplished by a single conductor, str ight or curved, having two sides substantially at right angles, one of which such as E2 of Fig. 5 lies adjacent to a face of the flange and the other such as the face at 63 (Fig. 6) lies adjacent to a cylindrical surface of the shaft without a second or opposite side conductor such 56 or an end conductor such as 58 joining the two side conductors, the return circuit from the one conductor being through some part, other than such opposite conductor. When such single conductor is used the frequency of the current employed must be such as to heat the required surface zones. When conductors are arranged in a loop and disposed relative to theflangcd shaft, as above described, satisfactory heating is accomplished with current of relatively low frequency, the single conductor requiring frequencies of a much higher order.

From the above description, it will be apparent that any selected zone or zones of a flange can be readily hardened with or without hardening other selected zones of the cylindrical part of the shaft by the apparatus as shown or with very simple modifications of it.

Other forms may be employed embodying the features of my invention instead of the one herein explained, change being made as regards the means and the steps herein disclosed, provided the elements stated by any of the following claims or the equivalent of such stated elements be employed, whether produced by my preferred method or by others embodying steps equivalent to those stated in the following claims.

I therefore particularly point out and distinctly claim as my invention:

1. The method of heat treating a flange having an axis of rotation comprising the steps of inserting a part of the flange between two generally parallel spaced inductor members so that the members lie on opposite sides of the flange and generally parallel with chordal elements of lateral faces of the flange and so that a peripheral surface of the flange lies in spaced relation with a generally axially disposed conductor, flowing periodically varying current through the inductor members and through the axially disposed conductor in series, the current in one inductor member being substantially opposite to that in the other member, and rotating the flange to distribute current in the flange to heat zones in the lateral faces and in the peripheral surface of the flange.

2. The method of heat treating surface zones of a flanged shaft having an axis of rotation comprising the steps of inserting a part of the flange between two generally parallel spaced inductor members so that the members lie on opposite sides of the flange and generally parallel with chordal elements of the lateral faces of the flange and so that a peripheral surface of the flange lies in spaced relation with a conductor connecting the inductor members, flowing periodically varying current through the inductor members and through the connecting conductor in series, the current in the inductor members being in reverse relation, moving the flange deeply enough into the space between the inductor members to bring a. flange-adjacent part of the shaft into heating proximity with an inductor member, and rotating the shaft and flange to distribute heating current in the flange and in the flange-adjacent part of the shaft to heat the flange and the said adjacent part of the shaft.

3. The method of heat treating surface zones of a flanged shaft comprising the steps of inserting a part of the flange between two spaced inductor members so that the members lie on opposite sides of the flange and generally parallel with chordal elements of lateral faces of the flange, moving the flange deeply enough into the space between the inductor members to bring a flange-adjacent part of the shaft into closely spaced relation with a part of an inductor member, the said part of the inductor member being formed to lie substantially in parallel relation with said part of the shaft, flowing periodically varying current through said inductor members in reverse series relation to heat a face of the flange and the flange-adjacent part of the shaft, and rotating the shaft to distribute heating in the flange and the flange-adjacent part of the shaft.

ALDEN O. WOOD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,024,906 Bennett Dec. 17, 1935 1,878,458 Blanchet Sept. 20, 1932 2,186,628 Dake Jan. 9, 1940 2,293,534 Denneen et a1 Aug. 18, 1942 2,297,878 Denneen et al Oct. 6, 1942 1,946,876 Northrup Feb. 13, 1934 2,268,527 Somes Dec. 30, 1941 2,170,130 Denneen et al Aug. 22, 1939 2,292,209 Denneen et al Aug. 4, 1942 2,326,674 Pavitt Aug. 10, 1943 FOREIGN PATENTS Number Country Date 435,343 British Sept. 19, 1935 OTHER REFERENCES Northrup, Practical Methods for Heating Solids by Induction, The Iron Age, Feb. 23, 1933, pages 310, 311, and 10, particularly page 310. (Copy in Sci. Lib.) 

